Process control systems are widely used in factories and/or plants in which products are manufactured or processes are controlled (e.g., chemical manufacturing, power plant control, etc.). Process control systems are also used in the harvesting of natural resources such as, for example, oil and gas drilling and handling processes, etc. In fact, virtually any manufacturing process, resource harvesting process, etc. can be automated through the application of one or more process control systems. It is believed the process control systems will eventually be used more extensively in agriculture as well.
Process control systems, like those used in chemical, petroleum or other processes, typically include one or more centralized or decentralized process controllers communicatively coupled to at least one host or operator workstation and to one or more process control and instrumentation devices, such as field devices, via analog, digital or combined analog/digital buses. Field devices, which may be, for example valves, valve positioners, switches, transmitters, and sensors (e.g., temperature, pressure and flow rate sensors), perform functions within the process such as opening or closing valves and measuring process parameters. The process controller receives signals indicative of process measurements or process variables made by or associated with the field devices and/or other information pertaining to the field devices, uses this information to implement a control routine and then generates control signals which are sent over one or more of the buses to the field devices to control the operation of the process. Information from the field devices and the controller is typically made available to one or more applications executed by an operator workstation to enable an operator to perform desired functions with respect to the process, such as viewing the current state of the process, modifying the operation of the process, etc.
The various devices within the process plant may be interconnected in physical and/or logical groups to create a logical process, such as a control loop. Likewise, a control loop may be interconnected with other control loops and/or devices to create sub-units. A sub-unit may be interconnected with other sub-units to create a unit, which in turn, may be interconnected with other units to create an area. Process plants generally include interconnected areas, and business entities generally include process plants which may be interconnected. As a result, a process plant includes numerous levels of hierarchy having interconnected assets, and a business enterprise may include interconnected process plants. In other words, assets related to a process plant, or process plants themselves, may be grouped together to form assets at higher levels.
Engineering a project for a process plant or a process control system is a complex process which starts at a conceptual phase and progresses through to the startup and operations of a process plant or process control system. During the engineering and design of a project, engineering details are pulled together covering the process and plant design, selection of instrumentation and control devices, selection of a control system, engineering of the control system, installation, commissioning and startup. These engineering details are captured in a variety of databases, and are pulled together into a common configuration system. The configuration system is used to generate reports for communication with end users, such as customers, generating project and process control strategy configuration. The reporting documents are often generated using standardized documentation tools, such as hypertext markup language (HTML), portable document format (PDF), Microsoft Word, Microsoft Visio, etc.
There are many aspects to configuring a distributed process control system, including, but not limited to, I/O, control strategy, batch, object linking and embedding (OLE) for process control (OPC) integration, history, displays, etc. The configuration system, and underlying database, provides tools and infrastructure for configuring a integrated solution to a process control system project. Configuration systems, such as DeltaV™ sold by Fisher-Rosemount Systems, Inc. of Austin, Tex., and configuration system applications, such as Explorer, Control Studio, Recipe Studio, Graphics Studio and User Manager each sold by Fisher-Rosemount Systems, Inc. of Austin, Tex., are used to configure the entire process control strategy, displays, I/O, alarm strategies, history and events, users and their roles, and every other part of the process control system. Such an arrangement works well, if the configuration system is in the central database, but this is not always the case.
The overall configuration process often extends beyond what the configuration system is designed to support. For example, I/O definitions, device specifications, unit requirements, and other information may be specified and configured using tools and databases that are separate from the configuration system. While using this information to configure the configuration system is very straightforward, it is often the case that the configuration databases use formats that are not understood by other design tools. These databases are also not understood by applications that project teams often work with as tools of choice across the entire project lifecycle, such as Microsoft Excel, Microsoft Word, SQL, Microsoft Visio, etc. Furthermore, not all members of a project team have the configuration system software installed, and often a project team wants to perform their work off-line using commonly available tools. Using such tools makes it much easier to exchange data with other contributors to the project, and to exchange data with the end-user. Once the off-line data is ready, the data needs to be imported to the configuration system. If the data is modified within the configuration system, or by another off-line database, then the modified data needs to be updated with the off-line database.
Further, project personnel add considerable value in consulting and writing specifications to make sure that the hardware and software design will meet the needs of the end user. Implementation, testing and documenting are done once the design has been approved. However, techniques to transfer such configuration details should be transferred into the configuration system, which may require interfaces and tools to translate the configuration details from one form to another and to transfer configuration details between off-line databases. Standardized objects simplify the development of project tools because they provide known data models to communicate with other teams on the project so that there is a clear definition of what data is required and when. They also help the project team quickly rejected bad or incomplete data. The standardized objects have been provided for the continuous control layer (e.g., loops, motors, valves, equipment modules, etc.), but the batch layer (e.g., phases, operations, procedures) has been standardized too a much lesser degree.